Testing an initial version of the implementation which estimates register pressure in SMS on libav micro benchmarks. I see 20% improvements in mjpegenc microbench and 11% on aacsbr-2 with SMS. However swscale-rgb24ToY_c still have spills in the final code although it requires maximum 64 VFP_REGS registers out of the available 64 registers so I'm trying to understand the reason for the spill.